Christians flee as militants expand control across Iraq

Tens of thousands of Christians have fled for their lives as Islamic State militants, the jihadist group previously known as Isis, surged across northern Iraq.

The militant group declared on Twitter it had seized 15 towns, a military base and the strategic Mosul dam on the Tigris River - though Kurdish officials claimed their forces retained control of the dam.

Islamic State militants stand guard after controlling a checkpoint in Khazer, close to the Kurdish region's border. Credit: Reuters

Islamic State fighters were seen controlling a checkpoint at a border area of the country's Kurdish region close to the heavily populated city of Arbil.

Islamic State fighters are targeting Iraq's majority Shi'ites and minorities such as Christians and Yazidis. Credit: Reuters

The ongoing offensive, which began at the weekend and has displaced as many as 200,000 people according to the United Nations, has alarmed the Baghdad government and world powers.